Electrical circuit



Feb 113, H KAVELER r 2,369,238

ELECTRICAL CIRCUIT Original Filed April 15, 1940 Illll INVENTORS R. G.P! ETY BY H H. KAVELER Patented Feb. 13, 1945 ELECTRICAL CIRCUIT HermanH. Kaveler, Bartlesville, kla., and Raymond G. Piety, Yonkers, N. Y.,assignors to Phillips Petroleum Company, a corporation of DelawareOriginal application April 15, 1940, Serial No. 329,810. Divided andthis application February 16, 1944, Serial No. 522,674

4 Claims.

This invention relates to an electrical circuit that is adapted, amongother things, to be employed to selectively fire one or more shots ormarkers in a well bore, and is a division of our copending applicationSerial No. 329,810, filed April 15, 1940.

While our present invention may be advantageously employed in variouslocales, as will be evident to persons skilled in the art, it is ofespecial utility when used with well equipment such as electricallyoperated gun periorators and the like.

It is the primary object of this-invention to provide electrical meansfor consecutively energizing a plurality of heating elements.

Another object of the instant invention is the provision of means of thecharacter indicated for electrically actuating apparatus associatedtherewith in a predetermined manner.

This invention has for a further object the electrical firing of a gunperforator or similar device.

These as well as other objects will be readily comprehended by referenceto the following detailed description and annexed drawing whichrespectively describe and illustrate a preferred embodiment of theinvention, and wherein Figure l is a diagrammatic vertical cross-sectionthrough a well bore showing apparatus suitable for placing desired typesof markers.

Figure 2 is a circuit diagram of an electrical circuit which is adaptedto be employed in conjunction with the apparatus of Figure 1.

With reference to Figure 1 of the drawing, the numeral 6 designates asuitable gun for firing the markers in the form of bullets into the wallof the bore hole 1. An electrically conductive cable 8 which is carriedby a reel 9 serves to position the marker gun in the well bore. Acollector ring and brush l0 on the reel provides electrical contactbetween the cable 8 and a conductor II on the surface of the earth towhich is attached a thr 'e-way switch l2. A battery l3, grounded to asuitable electrode such as the surface casing l4 in the bore hole, isconnected in such a manner that it will deliver a low voltage to onepoint of contact of the switch I2 and a high voltage through theresistance l5 and an ammeter IE to the other point of contact. Themarker gun 6 is similar in construction and operation to guns used forperforating the casing in a well bore. The bullets which are to serve asmarkers are contained in the bullet chambers I9 together with gun powderand heater wires for electrical ignition.

Figure 2 illustrates diagrammatically an electrical circuit which may beused for selectively firing the various shots. Conductor 20 is incontact with and receives electrical energy from cable 8. A series ofheating elements 2|, 22, and 23, for igniting the charges of gun powderare connected in parallel with branches including resistors 24, 25, 26,and fuse wires 21, 28, 29, respectively. Each of the heating elements isdesigned to ignite a charge of gun powder upon being supplied withcurrent from the low voltage contact of switch 2 and each fuse wire isdesigned to burn out upon being supplied with current from the highvoltage contact of switch l2. Interposed between the heating element 2|and the heating element 22 is a switch comprising a pair of contactpoints 30 and 3| which are urged into closing position but are held openby the fuse wire 21 as long as it remains intact. A similar switchcomprising contact points 32 and 33 is interposed between the heatingelement 22 and the heating element 23.

In operation, the marker in the bullet chamber containing the heatingelement 2| is fired into the formation by the operator by closing switch|2 on the low voltage contact. This sends current from the batterythrough the heating element which is destroyed upon igniting the charge.

The current from the battery may then flow only through the resistance24 and the fuse wire 21. The resistance 24 is high as compared with thetotal circuit resistance of the ground and of the cable 8 so that ahigher battery voltage is required to burn out the fuse 21. This highervoltage is applied to the fuse wire by closing switch |2 on the highvoltage contact. Upon the fuse 21 burning out, the contacts 30 and 3|are moved into closed position. The resistance I5 is high enough toprevent firing the second shot when the contacts 30 and 3| are closed.The second shot is fired by sending a large current at low voltagethrough the heating element 22 by closing switch |2 on low voltagecontact. To illustrate, if the resistance of the cable 8 plus theresistance of the ground return'from the gun to the grounded terminal ofthe battery is fifty ohms, the resistance. of the heating elements 2|,22, 23, twenty-five ohms each, and the current necessary to fire theshot is one ampere, then it is necessary to apply seventy-five volts atthe low voltage contact of switch |2. If the fuse wires 21, 28, 29, burnout at one quarter ampere and the resistances 24, 25, 26, are fourhundred ohms each and the resistance I5 is four hundred ohms, then itwill require about 212 volts at values of the resistances 24, 25, and26, difierent,

each from the others, that the operator could also determine the shotnumber by noting the ammeter indication.

It is to beunderstood that the form of our invention, herewith shown anddescribed, is to be taken as a preferred example of the same. and thatvarious changes with respect thereto may be made without departing fromthe spirit of the invention or the scope of the subjoined claims.

We claim:

1. An electrical circuit for consecutively energizing a plurality ofheating elements comprising a source of high electrical potential and asource of low electrical potential havin a common side, a resistanceelement having one side connected to the other side of the source ofhigh electrical potential, a line, a heating element connected betweenthe line and the common side of the sources of electrical potential, abranch circuit connected in parallel with the heating element, thebranch circuit including means for opening the same on the presence of amaximum current therein, a second heating element having one sideconnected to the common side of the sources of electrical potential, anelectrical contact connected to the line, an electrical contactconnected to the second heating element on the other side from thatconnected to the common side of the sources of electrical potential, thecontacts being in spaced relation, means operable on the opening of thebranch circuit to bring the contacts together and means for connectingthe line to the other side of the resistance element from that connectedto the source of high electrical potential, each heating element beingso designed that it is destroyed only when connected across the sourceof low potential, the branch circuit being so designed that it opensonly when the line is connected to the other side of the resistanceelement.

2. An electrical circuit for consecutively energizing a plurality ofheating elements comprising a source of high electrical potential and asource of low electrical potential having a common side, a resistanceelement having one side connected to the other side of the source ofhigh electrical potential, a line, a heating element connected betweenthe line and the common side of the sources of electrical potential, abranch circuit connected in parallel with the heating element, thebranch circuit including means for opening the same on the presence of amaximum current therein, a second heating element having one sideconnected to the common side of the sources of electrical potential, anelectrical contact connected to the line, an electrical contactconnected to the second heating element on the other side from thatconnected to the common side of the sources of electrical potential, thecontacts being in spaced relation, means operable on the opening of thebranch circuit to bring the contacts together and means for connectingthe line to the other side of the source of low electrical potential,each heating element being so designed that it is destroyed only whenconnected across the source of low potential, the branch circuit beingso designed that it opens only when the'line is connected to the otherside of the resistance element.

3. An electrical circuit for consecutively energizing a plurality ofheating elements comprising a source of high electrical potential and asource of low electrical potential having a common side, a resistanceelement having one side connected to the other side of the source ofhigh electrical potential, a line, a heating element connected betweenthe line and the common side of the sources of electrical potential, anelectrical fuse branch connected in parallel with the heating element, asecond heating element having one side connected to the common side ofthe sources of electrical potential, an electrical contact connected tothe line, an electrical contact connected to the second heating elementon the other side from that connected to the common side of the sourcesof electrical potential, the contacts being in spaced relation, meansoperable on the fuse burning out to bring the contacts together andmeans for connecting the line to the other side of the resistanceelement from that connected to the source of high electrical potential,each heating element being so designed that it is destroyed only whenconnected across the source of low potential, the fuse branch being sodesigned that it is burned out only when the line is connected to theother side of the resistance element.

4. An electrical circuit for consecutively energizing a plurality ofheating elements comprising a. source of high electrical potential and asource of low electrical potential having a common side, a resistanceelement having one side connected to the other side of the source ofhigh electrical potential, a line, a heating element connected betweenthe line and the common side of the sources of electrical potential, anelectrical fuse branch connected in parallel with the heating element, asecond heating element having one side connected to the common side ofthe sources of electrical potential, an electrical contact connected tothe line, an electrical contact connected to the second heating elementon the other side from that connected to the common side of the sourcesof electrical potential, the contacts being in spaced relation, meansoperable on the fuse burning out to bring the contacts together andmeans for connecting the line to the other side of the source of lowelectrical potential, each heating element being so designed that it isdestroyed only when connected across the source of low potential, thefuse branch being so designed that it is burned out only when the lineis connected to the other side of the resistance element.

HERMAN H. KAVELER. RAYMOND G. PIETY.

